This invention relates to a detection apparatus suitable for use in detecting the presence of skew or asymmetry in one or more of the leading edge high lift surfaces of a leading edge high lift surface system of an aircraft wing. The apparatus may also be suitable for use in other applications.
Leading edge high lift surface systems are used to vary the camber of the leading edge of an aircraft wing, thus altering the effective shape of the aerofoil defined by the wing. As a result, for a given airspeed and angle of attack, the level of lift which can be achieved can be varied as the effective curvature of the wing can be changed by a small amount. Further, a greater angle of attack can be attained prior to stall. Typically, the leading edge high lift surfaces are used during landing to permit sufficient levels of lift to be generated at reduced airspeeds, and during takeoff to achieve more lift with a steeper climb.
Each aircraft wing is typically provided with several leading edge high lift surfaces. Each surface is typically moved or adjusted using two actuators, the actuators of each surface being driven by a common drive arrangement. In the event of the failure of one of the actuators associated with one of the surfaces, that surface will become skewed. As a result, the angle of attack which can be maintained by the wing for a given airspeed without stalling will change. It is an object of the invention to provide an apparatus permitting the detection of such a skewed surface, thereby permitting appropriate remedial action to be taken.
If both of the actuators associated with one of the surfaces fail, then that surface will not move when the remaining surfaces move. Such a situation is known as an asymmetry and is undesirable for the reasons discussed hereinbefore in relation to skewed surfaces and it is desirable to permit the detection of such an asymmetry.
According to the present invention there is provided a detection apparatus for use with a system having a plurality of moveable surfaces, the apparatus comprising signal transmission means extending across each said surface, a signal generator, a signal receiver and signal interruption means associated with adjacent ones of the said surfaces and arranged to interrupt the transmission of a signal along the signal transmission means upon relative movement of the adjacent ones of the surfaces occurring.
The apparatus is particularly suitable for use with a leading edge high lift system of an aircraft wing having a plurality of moveable leading edge high lift surfaces.
The signal interruption means is conveniently arranged to permit a small amount of relative movement between adjacent surfaces without interrupting the transmission of a signal along the signal transmission means.
The signal transmission means may comprise an optical fibre, or alternatively may comprise an electrically conductive wire. The signal transmission means is conveniently provided with a protective sleeve.
The signal transmission means may be composed of a plurality of segments, each segment extending across a respective one of the surfaces, the signal interruption means comprising plug and socket arrangements arranged to become disconnected upon relative movement of adjacent surfaces occurring.
Alternatively, the signal transmission means may be continuous, the signal interruption means being arranged to break the signal transmission means in the event of relative movement of adjacent ones of said surfaces occurring.
Preferably, the signal interruption means comprises a first component carried by a bracket associated with one of the surfaces, and a second component carried by a bracket associated with an adjacent one of the surfaces. The brackets are conveniently provided with slots within which the components can slide to permit a limited amount of relative movement of the surfaces to occur without interrupting the signal.
The components are conveniently rotatable relative to the brackets and are conveniently arranged to cooperate with one another along a plane angled relative to the axes of the components.
In such an apparatus, upon a significant level of relative movement of adjacent surfaces occurring, the signal interruption means prevents the transmission of signals along the transmission means. Upon the receiver failing to receive a signal transmitted by the signal generator, a warning signal indicative of the presence of a skew or asymmetry is produced whereon appropriate remedial action can be taken to minimize the effect of the skew or asymmetry.